Evercoat Fibreglass 2233 Uro-Fill Activator - Quart Mix 1 part URO-FILL Activator to 4 parts URO-FILL Primer Surfacer Superior adhesion to bare steel, body filler, fiberglass and treated aluminum Easily finish sands in one step with fine grit sandpaper Two component, provides a thorough cross-link cure with no shrinkage Supplied at spray viscosity; no reduction required